My research is focused on elucidating the cellular and molecular mechanisms that microRNAs play in cancer. microRNA (miRNA) molecules have emerged as important regulators of many biological processes, including cancer. It is known that many tumor suppressor miRNAs are lowly-expressed in cancer. However, the ability of these miRNAs to restrain tumor progression and whether miRNAs can be therapeutically delivered to treat cancer is not well established in vivo models. The project proposed within this K99/R00 award outlines the creation and implementation of novel conditional miRNA expression system, nano-particle delivery system, and miRNA target identification pipelines that allow studying microRNA in mouse and human cancer models. The research proposed within this application has been shaped by my experiences studying p53 tumor- suppressor gene restoration, identifying tumor suppressors in liver cancer, performing in vivo shRNA screen, and by my recent efforts to elucidate the therapeutic effects of NF-kB inhibitors in lung cancer. These research projects solidified my interests in pursuing a career studying the fundamental biology of tumor suppressor miRNA in human cancer progression and therapy because miRNAs like miR-34 are emerging mediators of important tumor suppressive pathways. The systems that we propose herein utilize autochthonous mouse models and genetically defined human cancer cells. This study will integrate genetics, bioinformatics and translational nano-technology to study miR-34's function in lung cancer development and evaluate miR-34 family as a potential therapeutic agent for lung cancer. The facilities at the Koch Institute at MIT, and the expertise that my mentor, Dr. Jacks, can provide will be invaluable for successful implementation of this project. The goals of these experiments outlined within are: Elucidating the mechanisms by which miR-34a inhibits lung tumor progression; Develop nano-technology to systematically deliver miR-34a in mouse and human lung tumor models; Identify and validate novel miR-34a target genes relevant to human lung cancer The research environment in the Jacks Laboratory, MIT, and the surrounding area offers unmatched opportunities for scientific discussion, collaboration, and training. Currently, I supervise an undergraduate student and a technical assistant that work directly with me on experiments pertaining to my research. This is an incredible experience that will endow me with many of the necessary skills to manage an independent laboratory. The scientific community at MIT, the Broad Institute, and Harvard Medical School offers countless seminars and workshops that will continue to foster my scientific development. My immediate goals are to develop the research platform described in this application and to demonstrate its potential to uncover molecular and cellular mechanisms of miR-34a and other tumor suppressor miRNAs. It is my intention to start an independent research program that will capitalize on these in vivo systems by studying tumor-suppressor miRNAs in a variety of tumor models. For the long-term, I am confident that these experiments will provide a solid foundation on which my research program can be built upon. I look forward to educating and recruiting students and postdocs that share my passion for cancer research.